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Copy Disk Image as Folder

When you open a .dmg file, a disk image is mounted. You are then generally supposed to copy the contents of that disk image to your hard drive (to your Desktop, your Applications folder, or wherever). But what if you want to copy the whole disk image, including all its contents, as a folder? Hold the Option key, and drag the "proxy icon" in the title bar of the disk image window to the destination in the Finder.

Ecrix's VXA-1 Tape Drive: Big Fast Backups

Huge hard disks are a boon in today's world of MP3s and QuickTime movies, but they've made reliable backup strategies harder to develop. Back when I bought my first 2.6 GB DAT drive, I'd just added my first 1 GB hard disk to my main Mac, and no other Mac on my network had over 700 MB online. With Retrospect's intelligent snapshot approach to backup and incremental backups, a couple of tapes would last for months. Now it takes me 8 DAT tapes just to do the first backup, and I can go only about a month before I need to recycle a 13-tape backup set. Worse, because of the swapping necessary to write and verify 8 tapes, it takes four or five days to finish that initial backup, during which time the work I do remains largely unprotected.

So when the folks at Ecrix (pronounced "ecree") offered to send me a review unit of their new VXA-1 tape drive, I jumped at the chance, although I warned them that a serious review of a backup device would take a long time, since the true test of a backup device is how it performs under real world conditions. I've now been using a VXA-1 tape drive for about eight months, and I think I understand it well.

Big and Fast -- Ecrix makes much of their tape technology and how it supposedly makes the special tapes written by the VXA-1 more reliable and durable than other approaches. Although I've had no data loss problems, I can't comment on the super durability, since I wasn't about to dip my test tapes in boiling coffee or freezing water. What sets the VXA-1 apart in my eyes is that its tapes hold a lot of data, and it can read and write at blinding speeds.

Ecrix claims that their V17 tapes hold up to 66 GB of data, though that's with hardware compression. They also claim a 6 MB per second (360 MB per minute) write speed, and that number also takes hardware compression into account. It's generally more useful to discuss backup devices in terms of native speeds and capacities, which would be 33 GB of data and 3 MB per second (180 MB per minute), not because you won't do somewhat better with compression, but because you'll be happier if the drive exceeds your expectations rather than falling short.

For instance, when I paired the SCSI version of the VXA-1 with an Adaptec 29160 SCSI card in my 450 MHz Power Mac G4, Retrospect reported write speeds around 250 MB per minute. That's well above the 180 MB per minute that you'd see without compression, but far below the 360 MB per minute Ecrix claims. Throughout this article, I'll use the native speed and capacity, and when comparing the VXA-1 with other tape drives, you should make sure to do the same for an accurate comparison.

Based purely on specs, the VXA-1 may sound like a solid backup device - big, fast, and reliable. That's essentially my conclusion, but I want to focus first on the negatives, since although the VXA-1 is very good, it's not perfect, and what I've learned may be of use to anyone considering these extremely attractive backup devices.

Speed Caveats -- You may be salivating at the idea of backing up 250 MB per minute, but you won't see speeds like that in most situations.

You must connect the VXA-1 to a fast Mac. I first used it on an old Power Mac 7100, but even backups of the local hard disk proceeded at only about 30 MB per minute. Plus, I had to order a special cable to connect the 68-pin high-density connectors on the VXA-1 to the 25-pin SCSI port on the 7100. Even a less expensive Adaptec 2930 SCSI card in my Power Mac G4 turned in about 200 MB per minute. So if you like to dedicate an older Mac to backup tasks, you might want to reconsider that with a VXA-1. (Ecrix has recently released a FireWire version of the drive that reportedly sports similar performance to the SCSI version in conjunction with a fast SCSI card.)

The VXA-1 itself is seldom the performance bottleneck. If you're backing up other machines across a network, performance suffers significantly based on the network speed and the speed of the Mac being backed up. The faster Macs on our network, my PowerBook G3 and Tonya's iBook, reach respective speeds of about 55 MB per minute (transferring over 10 Mbps wired Ethernet) and 40 MB per minute (over our 11 Mbps AirPort wireless network). Our Performa 6400 manages only about 30 MB per minute over Ethernet, and the aged SE/30 hovers around 5 MB per minute. So, although you can't blame the VXA-1 for slow network backup performance, it's a fact of life you can fix only by increasing the speed of your network or the Macs being backed up. And realistically, it's mostly an issue on initial backups, since incremental backups copy much less data per session.

Capacity Caveats -- There are also some caveats when considering that 33 GB capacity. First off, Ecrix actually sells tapes in three different capacities. The $30 V6 cartridge has a 12 GB native capacity. The $45 V10 cartridge checks in at 20 GB native, and the $80 V17 cartridges that I've been using have the longest tape length, so they provide 33 GB native. The 20 GB V10 is the most economical per gigabyte, by a bit, but I'd happily pay a little more for the V17's extra capacity.

As I noted before, almost all tape drives claim a 2:1 ratio for their hardware compression. The claim is relatively accurate for standard types of documents, but many of the largest files we work with today (MP3s, QuickTime movies, and JPEG graphics) are already internally compressed. No lossless compression routine such as those used in backup devices or programs like Aladdin's StuffIt Deluxe can achieve a 2:1 compression ratio on such files, and in the worst case, the files may even grow slightly.

But there's yet another problem that can suck capacity from your backup tapes. For optimal use of space with any tape drive, you never want the drive to wait for data from the computer. Most tape drives write "pad blocks" while waiting since it's faster for a drive to write pad blocks rather than stop, rewind, reposition, spin back up to speed, and start writing again. The VXA-1 is different: it does stop the tape motion while waiting for data, but it must still write a "splice point" between the old and new data, and the accumulation of many splice points reduces capacity. So if you're using a slow Mac or backing up over a network, you're likely wasting some space.

I ran into a combination of these two issues in spades. Since most of my backups run over 10 Mbps Ethernet, they're not very speedy, and until I moved the VXA-1 from the Power Mac 7100 to my Power Mac G4, nothing was backing up at much over 25 MB per minute. Worse, about 9 GB of the files on our Performa 6400 file server are MP3s. Needless to say, I was unwittingly wasting considerable tape space and was miffed when my tapes only held about 29 GB. It wasn't until Ecrix's tech support explained things that I realized how badly I'd been using the VXA-1.

I've come up with two solutions. First, I'm going to stop backing up my MP3s to tape and instead burn them to CD-R, which will provide some level of backup and let me play MP3s in a Philips CD-MP3 player a friend gave us for Christmas. Second, you can use an Ecrix program called VXATool to change some of the configuration settings within the VXA-1. One of these options sets the drive to favor capacity over speed (supposedly making a V17 tape hold its full 33 GB versus only 20 GB when speed is favored), and I've just switched to that mode. It reduced the speed of an initial backup of my Power Mac G4's hard disk from 250 MB per minute down to 135 MB per minute, but the throughput of subsequent incremental backups and for all my network volumes was unaffected. I haven't been using it long enough to determine how much more data I'll really get on each tape. Unfortunately, VXATool is a primitive command-line program; the command to favor capacity is "1 capacity y".

Other Considerations -- I was initially quite negative about moving the VXA-1 from the 7100 in the server room to the G4 at my desk because I like having Retrospect's backup server scripts running constantly and I don't like listening to unnecessary fans. Retrospect turned out not to be a problem, since it politely launches itself every night at 11 PM (thanks to the Retro.Startup extension), backs up everything on the network, and doesn't complain when I quit it in the morning after a glance to verify the backups completed successfully. More important, the VXA-1's fan, although relatively loud, turns on only when necessary, so it's mostly silent.

The physical design of the VXA-1 is quite large, though reasonably attractive, and it can sit on either its bottom or on its side. Four front panel lights flash in a variety of ways and colors to communicate numerous bits of feedback. Unfortunately, the key to what those lights mean exists only in Ecrix's PDF-based documentation (even though they include a printed Getting Started card).

I've had to interpret the feedback lights twice. The first time it informed me that I needed to clean the drive with the special $35 cleaning tape. The second was more serious - the first unit I received, an early production model, stopped working and announced its troubles via the feedback lights. I tried to troubleshoot it with the aid of Ecrix's tech support, and when updating its firmware didn't solve the problem, they promptly replaced it with a current model that's worked well since, with one exception.

At that point, I was still using the Power Mac 7100, and something caused it to crash while writing to tape. Sophisticated Circuits' Rebound restarted the Mac, but the VXA-1 remained confused (other crashes haven't bothered it at all) and claimed it was continuing to write to the tape. I couldn't stop it or even eject the tape. Ecrix explained that in such a situation, the VXA-1 tries to write the directory of what has been stored on the tape, and it can remember that it wants to do so even if you power it off and back on again. Something prevented it from completing that write, so Ecrix's tech support rep told me the secret trick for ejecting a tape in such a situation: hold down the front-mounted eject button for 10 to 15 seconds and the VXA-1 will cough it up. Needless to say, you'll want to erase that tape and start a new backup on it, since its data is not likely to be in a good state.

Buying Advice -- Despite these warts, I'm actually more comfortable recommending the VXA-1 now that I've lived with it for the last eight months. Ecrix's tech support has not only been able to help resolve my problems, they've explained why they've occurred. To me, knowledge of how and why my systems work is important because I'm relying on this drive to act predictably in unpredictable situations.

The cost per gigabyte of the VXA-1's tapes is extremely good, but the drive itself isn't as cheap for use on home networks or small offices. Prices range from about $1,000 up to $1,500, depending on whether you want an internal or external drive, FireWire or SCSI, and with or without Retrospect Desktop or Retrospect Server. However, even as Ecrix provides various stripped-down options, they don't skimp - even the most minimal package includes a $35 cleaning tape and an $80 V17 tape. Plus, you can get any package to test for free for 30 days.

For home and small office use, OnStream's 25 GB and 15 GB (native capacities) Echo tape drives, which come in USB, FireWire, and SCSI versions, would seem to compete favorably with the VXA-1. Drive costs are significantly lower than the VXA-1 drives, particularly for the slow 15 GB USB drives, but the tape capacities are also lower, the performance is slower, and the cost per gigabyte for the 15 GB tapes is higher than the VXA-1's 33 GB tapes. I can't speak to the OnStream drives' overall reliability or usability.

Plus, if you're anticipating future growth, Ecrix offers the VXA AutoPak, a 15 tape loader combined with either one or two VXA-1 drives. It's pricey, but not for what you get, and lets you start small and move up without changing media types.

One slight concern about both the Ecrix and OnStream drives is that neither is yet an industry standard with multiple suppliers for media and mechanisms. That's a concern if you think that either company might go under, orphaning users who would need new media or replacement mechanisms to recover backed-up data. Since neither technology has reached the status of industry standard, they're equally vulnerable, and anyone who is truly concerned should either look elsewhere or make contingency plans.

In the end, I'm not only happy with the VXA-1 drive, I'm extremely pleased with how it has compared to my old, slow DAT drive and its teetering stacks of tapes. If your backup strategy is suffering from too-old hardware, take advantage of the 30-day free trial of the VXA-1 and see if it solves your problems as handily as it solved mine.